Neuroparalytic keratitis, the degenerative corneal change that follows trigeminal nerve injury, is an important problem for clinicians that manage patients with trigeminal neuralgia. Most therapeutic procedures that relieve the pain of trigeminal neuralgia must cuase some degree of trigeminal denervation. Despite refinements of technique, neuroparalytic keratitis and the subsequent loss of visual acuity continue to be a clinical problem. While many theories have been proposed to explain the pathogenesis of neuroparalytic keratitis, we believe that the loss of peptide containing nerve fibers from the cornea (which occurs with trigeminal denervation) is central to the pathogenesis. To develop evidence in support of this hypothesis we propose to implant peptidergic neurones (from trigeminal and dorsal root ganglia) into the anterior chambers of the eyes of adult rats. After these grafts have become established, we propose to lesion the ophthalmic nerve and observe if the grafts can reinnervate the cornea and protect against the development of neuroparalytic keratitis. Eyes with non-peptidergic grafts will serve as controls. These pilot studies will advance the understanding of the pathogenesis of neuroparalytic keratitis and could offer important insights into effective therapeutic protocols to manage this difficult problem.